Enzymatic bioleaching of metals from printed circuit board

Abstract

Enzymes are powerful tool that help to maintain an unpolluted environment through their use in waste management. Enzymatic bioremediation is potentially a rapid method for removal of pollutants. Therefore, the present study has been carried out to investigate the possibility of bioleaching of metals from printed circuit board (PCB) powder by enzymatic bio-Fenton process. To do this glucose oxidase enzyme was used for in situ production of hydrogen peroxide (H2O2). The H2O2 was further used in Fenton’s reaction for conversion of Fe(II) into Fe(III). Effects of various parameters such as incubation time, temperature, pH, and shaking speed on conversion of Fe(II) into Fe(III) were assessed. This enzymatic bio-Fenton process was further applied for bioleaching of metals. The results showed that metal recovery increased with an increase in initial Fe(II) concentration. Maximum recovery of metals was achieved at 250 mM initial Fe(II) concentration. The metal recovery decreased with an increase in concentration of PCB powder. The present research put forth a novel method for bioleaching of metals.